NSUF 15-595: A Bootstrapping Approach to Optimizing the Fidelity of Ion Versus Neutron Irradiations
Due to the high costs and extended times required for neutron irradiations and the associated post irradiation examinations, charged particle (CP) studies are emerging as a proposed technique to emulate neutron irradiations. However, an even more important reason is that current test reactors simple cannot reach the high doses targeted, in some cases to 400 dpa or more, for advanced materials needed in some future power reactor designs. Unfortunately, it is well established that interpreting (translating) CP irradiation results to predict neutron irradiation effects is beset with a number of confounding factors, not the least being the intrinsic effects of highly accelerated dpa rates. Physical models can be developed to assist the CP-neutron irradiation translations; however, sufficiently detailed understanding of the complex multiphysics-multiscale mechanisms involved is not yet in hand. Recently an Integrated Research Program (IRP) was funded (PI G.S.Was) which addresses the grand challenge of CP-neutron emulation. However even if the IRP is it is successful by some metric, CP irradiations cannot empirically be proven to work under conditions of extreme dpa extrapolations that are required in some cases. Here we propose to use the RTE to initiate a fundamental study which would greatly complement the much larger IRP effort. Our study will systematically address CP-neutron irradiation translations using a new and innovative bootstrapping approach. This involves comparing samples at a constant dose from irradiations by only neutrons, only CP, or neutrons followed by CP over varying bootstrapped increments of dpa. An illustrative example would involve neutrons to (say) 30 dpa, CP to 30 dpa and neutrons to 15 plus CP from 15 to 30 dpa. All three conditions at 30 dpa would be compared and contrasted. Such bootstrapping will permit: a) systematic comparisons of CP-neutron irradiation conditions as a basis to model various regimes of microstructural and mechanical property evolutions; and b) to test the hypothesis that it may be possible to use CP irradiations to extrapolate the response of previously pre-seeded neutron irradiated conditions to a higher dpa where the dominant microstructural evolution path was previously established by neutrons. The RTE proposal itself will only fund time on a hot Focused Ion Beam tool at the University of California, Berkeley to develop procedures for creating liftouts from neutron irradiations that can then be subsequently ion irradiated. The FIB liftout development portion of this research can be completed in a period of 6 months.
Additional Info
| Field | Value |
|---|---|
| Abstract | Due to the high costs and extended times required for neutron irradiations and the associated post irradiation examinations, charged particle (CP) studies are emerging as a proposed technique to emulate neutron irradiations. However, an even more important reason is that current test reactors simple cannot reach the high doses targeted, in some cases to 400 dpa or more, for advanced materials needed in some future power reactor designs. Unfortunately, it is well established that interpreting (translating) CP irradiation results to predict neutron irradiation effects is beset with a number of confounding factors, not the least being the intrinsic effects of highly accelerated dpa rates. Physical models can be developed to assist the CP-neutron irradiation translations; however, sufficiently detailed understanding of the complex multiphysics-multiscale mechanisms involved is not yet in hand. Recently an Integrated Research Program (IRP) was funded (PI G.S.Was) which addresses the grand challenge of CP-neutron emulation. However even if the IRP is it is successful by some metric, CP irradiations cannot empirically be proven to work under conditions of extreme dpa extrapolations that are required in some cases. Here we propose to use the RTE to initiate a fundamental study which would greatly complement the much larger IRP effort. Our study will systematically address CP-neutron irradiation translations using a new and innovative bootstrapping approach. This involves comparing samples at a constant dose from irradiations by only neutrons, only CP, or neutrons followed by CP over varying bootstrapped increments of dpa. An illustrative example would involve neutrons to (say) 30 dpa, CP to 30 dpa and neutrons to 15 plus CP from 15 to 30 dpa. All three conditions at 30 dpa would be compared and contrasted. Such bootstrapping will permit: a) systematic comparisons of CP-neutron irradiation conditions as a basis to model various regimes of microstructural and mechanical property evolutions; and b) to test the hypothesis that it may be possible to use CP irradiations to extrapolate the response of previously pre-seeded neutron irradiated conditions to a higher dpa where the dominant microstructural evolution path was previously established by neutrons. The RTE proposal itself will only fund time on a hot Focused Ion Beam tool at the University of California, Berkeley to develop procedures for creating liftouts from neutron irradiations that can then be subsequently ion irradiated. The FIB liftout development portion of this research can be completed in a period of 6 months. |
| Award Announced Date | 2015-08-10T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Peter Hosemann |
| Irradiation Facility | None |
| PI | G. Robert Odette |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 595 |